Assessment of the Short-Term Effects of Weather Conditions on Mass Mortality of the Saiga Antelope in Kazakhstan

The critically endangered saiga antelope (Saiga tatarica tatarica) was subject to a catastrophic mortality event during calving in May 2015, Central-Kazakhstan. More than 140,000 antelopes, representing approximately half of the global population, were estimated to have died, but the causes are unclear.

One of the hypotheses is that an environmental factor triggered
the precipitation of a polymicrobial disease, primarily
haemorrhagic septicaemia caused by Pasteurella multocida serotype
B.

This study describes gross pathological findings obtained during
field investigations and tests if weather conditions preceding the
outbreaks acted as a common trigger. For this purpose, weather
conditions at different known die-off sites were compared with
those from unaffected sites, using meteorological data from
regional, ground-based weather stations.

To verify if datasets from regional stations adequately reflect
weather conditions on calving sites, variation with weather records
collected on-site was determined. Subsequently, weather records
from before the die-offs in 2015 were assessed for consistencies
and compared to datasets from a calving aggregation in a non-
outbreak year (2014) and from die-offs in the Ural population in
2010 and 2011.

Finally, divergence of weather values in May 2015 from long-term
climatic normals was determined. The pathologies observed during
post-mortem examinations were consistent with haemorrhagic
septicaemia and clostridial enterotoxaemia, with Clostridium
perfringens being a potential secondary factor in the polymicrobial
disease. While weather patterns preceding the 2015 die-offs did
show some similarities, there were also substantial variations.
Temperature variation was the only parameter consistent across all
2015 die-off sites and significantly different from 2014, however
the implication of this is debatable.

Overall, no evidence was found for the influence of
meteorological variables on the onset of disease in saigas. The
agreement between on-site and regional weather records was
generally moderate and very low for relative humidity records,
which could be useful information for future meteorological
research in the region.